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We discuss the connection among three distinct classes of models often used to explain the late cosmic acceleration: decaying cosmological term, bulk viscous pressure, and nonlinear fluids. We focus on models that are equivalent at zeroth…

Astrophysics · Physics 2007-05-23 Sandro Silva e Costa , Martin Makler

The cosmological constant, i.e., the energy density stored in the true vacuum state of all existing fields in the Universe, is the simplest and the most natural possibility to describe the current cosmic acceleration. However, despite its…

Astrophysics · Physics 2008-11-26 S. Carneiro , M. A. Dantas , C. Pigozzo , J. S. Alcaniz

In this paper, we attempt to explore the possibility of a obtaining a viable emergent universe scenario supported by a type of fluid known as the extended Chaplygin gas, which extends a modification to the equation of state of the well…

General Relativity and Quantum Cosmology · Physics 2025-08-13 Rikpratik Sengupta , Anirban Chanda , B C Paul , M Kalam

We show that the Einstein field equations with a negative cosmological constant can admit black hole solutions whose thermodynamics coincides with that of logotropic fluids, recently investigated to heal some cosmological and astrophysical…

General Relativity and Quantum Cosmology · Physics 2023-02-28 Salvatore Capozziello , Rocco D'Agostino , Alessio Lapponi , Orlando Luongo

In cosmology an important role is played by homogeneous and isotropic solutions of the Einstein-Euler equations and linearized perturbations of these. This paper proves results on the asymptotic behaviour of scalar perturbations both in the…

Analysis of PDEs · Mathematics 2009-06-16 Paul T. Allen , Alan D. Rendall

We analyze the properties of a generic cosmological fluid described by the van der Waals equation of state. Exact solutions for the energy density evolution are found as implicit functions of the scale factor for a flat…

General Relativity and Quantum Cosmology · Physics 2016-02-11 Rudinei C. S. Jantsch , Marcus H. B. Christmann , Gilberto M. Kremer

We study the large-time behavior of finite-energy weak solutions for the Vlasov-Navier-Stokes equations in a two-dimensional torus. We focus first on the homogeneous case where the ambient (incompressible and viscous) fluid carrying the…

Analysis of PDEs · Mathematics 2025-12-02 Raphaël Danchin , Ling-Yun Shou

We discuss the cosmology of axion-scalar systems in asymptotic limits of type IIB/F-theory flux compactifications. These results allow us to test a putative extension of the Distance Conjecture in a dynamical setting, which posits that…

High Energy Physics - Theory · Physics 2026-05-12 Filippo Revello

We study the asymptotic behavior of global solutions to hydrodynamical systems modeling the nematic liquid crystal flows under kinematic transports for molecules of different shapes. The coupling system consists of Navier-Stokes equations…

Analysis of PDEs · Mathematics 2012-10-24 Hao Wu , Xiang Xu , Chun Liu

Several isotropic, homogeneous cosmological models containing a self-interacting minimally coupled scalar field, a perfect fluid source and cosmological constant are solved. New exact, asymptotically stable solutions with an inflationary…

General Relativity and Quantum Cosmology · Physics 2009-10-28 Luis P. Chimento , Alejandro S. Jakubi

In this paper, the dynamical heteroclinic orbit and attractor have been employed to make the late-time behaviors of the model insensitive to the initial condition and thus alleviates the fine tuning problem in cosmological dynamical system…

Astrophysics · Physics 2020-05-13 Xin-zhou Li , Yi-bin Zhao , Chang-bo Sun

We investigate spatially flat isotropic cosmological models which contain a scalar field with an exponential potential and a perfect fluid with a linear equation of state. We include an interaction term, through which the energy of the…

Astrophysics · Physics 2008-11-26 Andrew P. Billyard , Alan A. Coley

We consider a self-consistent system of Bianchi type-I (BI) gravitational field and a binary mixture of perfect fluid and dark energy given by a cosmological constant. The perfect fluid is chosen to be the one obeying either the usual…

General Relativity and Quantum Cosmology · Physics 2015-05-01 Bijan Saha

A one-component dark energy fluid model of the late universe is considered ($w<-1$) when the fluid, initially assumed laminar, makes a transition into a turbulent state of motion. Spatial isotropy is assumed so that only the bulk…

General Relativity and Quantum Cosmology · Physics 2016-03-02 Iver Brevik

A particular generalization of the Chaplygin inflationary model, using the formalism of Hamilton-Jacobi and elliptic functions, results in a more general non-linear Chaplygin-type equation of state (Chaplygin-Jacobi model). We investigate…

General Relativity and Quantum Cosmology · Physics 2025-03-11 J. A. S. Fortunato , W. S. Hipolito-Ricaldi , N. Videla , J. R. Villanueva

We investigate the late-time cosmic acceleration within the framework of viscous $f(T,L_m)$ gravity, where the gravitational action depends on both the torsion scalar $T$ and the matter Lagrangian $L_m$. In this context, the Universe is…

General Physics · Physics 2026-03-24 M. Koussour , Alnadhief H. A. Alfedeel , S. Muminov , J. Rayimbaev

We consider a spatially flat FLRW universe. We assume that it is filled with dark energy in the form of logotropic dark fluid coupled with dark matter in the form of a perfect fluid having a barotropic equation of state. We employ dynamical…

General Relativity and Quantum Cosmology · Physics 2022-02-03 Goutam Mandal , Sujay Kr. Biswas , Subhajit Saha , Abdulla Al Mamon

We test the viability of a single fluid cosmological model containing a transition from a dark-matter-like regime to a dark-energy-like regime. The fluid is a k-essence scalar field with a well-defined Lagrangian. We constrain its model…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-18 Iker Leanizbarrutia , Alberto Rozas-Fernández , Ismael Tereno

We study the phase space dynamics of cosmological models in the theoretical formulations of non-minimal metric-torsion couplings with a scalar field, and investigate in particular the critical points which yield stable solutions exhibiting…

General Relativity and Quantum Cosmology · Physics 2017-08-18 Arshdeep Singh Bhatia , Sourav Sur

Using anisotropic hydrodynamics, we examine the existence of early-time attractors of non-conformal systems undergoing Bjorken expansion. In the case of a constant mass, we find that the evolution of the scaled longitudinal pressure is…

Nuclear Theory · Physics 2023-05-01 Mubarak Alqahtani